| Idiom | Definition | Usage | 
				
					| JACK 
					OF ALL TRADES | 
 a person who knows a little about a lot of different 
					subjects or activities, but not a lot about any one of them
 
 The expression is part of the saying “He’s a jack of all 
					trades but a master of none.” Being described as a jack of 
					all trades can be either a compliment (usually when it is 
					used without the second half of the saying) or an insult 
					(when it occurs in the saying and the emphasis is on the 
					fact that one is master of none).
 | 1. Walt is good at so many things: he can fix the plumbing 
					and wiring in his house, he fixed his roof when it leaked, 
					he installed his washer and dryer, and he paints the house 
					when it needs it. He’s really a jack of all trades. 
 2. The position in the company required someone who knew 
					everything about a very narrow subject. They weren’t looking 
					for a jack of all trades.
 | 
				
					| jack up | increase | Stores typically 
					jack up prices during the holidays. | 
				
					| jam on the 
					brakes | stop the car suddenly | Because of the cow on 
					the road she had to jam on the brakes. | 
				
					| jam-packed | crowded | This club is really 
					popular and always jam-packed. | 
				
					| jazz 
					it up |  |  | 
				
					| jerking someone 
					around | causing me trouble | Recently it seems like 
					everyone is jerking me around. | 
				
					| jockeying for 
					position | maneuvering to get an 
					advantage | The candidates for the 
					presidency were jockeying for position. | 
				
					| John Doe | unknown person | Another John Doe 
					was driving while intoxicated. | 
				
					| JOHN 
					HANCOCK | one’s signature | 1. If you’ll just put your John Hancock on this line at the 
					bottom of the contract, you can drive the car away right 
					now. 
 2. They sent the check back because he forgot to put his 
					John Hancock on it. The expression refers to the signature 
					of the first person to sign the American Declaration of 
					Independence in 1776. John Hancock’s signature was larger 
					than the others and stood out clearly.
 | 
				
					| John Henry | signature | Please put your 
					John Henry on the application form. | 
				
					| JOHNNY 
					COME LATELY | a newcomer 
 Compare to: wet behind the ears
 
 The expression is used to dismiss someone’s importance due 
					to a lack of experience.
 | 1. You can’t expect to join the company, take over 
					immediately, and not cause some hard feelings. To the 
					workers, you’re a Johnny come lately. 
 2. The author of the book was under attack because he was a 
					Johnny come lately to the field and didn’t have the 
					reputation that the older, more established authors had.
 | 
				
					| Johnny-on-the-spot | in the right place at 
					the right time | He always seems to be
					Johnny-on-the-spot. | 
				
					| jump all over 
					someone | scold me | For no reason, he began 
					to jump all over me. | 
				
					| jump at | quickly accept | She knew that he would
					jump at the chance to go to Japan. | 
				
					| jump down one's 
					throat | yell at him | She began to 
					jump down his throat over being late. | 
				
					| jump on someone | scold | The boss would 
					jump on him for even a small mistake. | 
				
					| jump 
					on the bandwagon |  |  | 
				
					| jump out of 
					one's skin | be badly frightened | She looked as if she 
					would jump out of her skin while she was 
					watching the horror movie. | 
				
					| JUMP 
					THE GUN | to do something prematurely; to start early, before all the 
					preparations have been made. 
 The expression probably originates from foot racing, in 
					which an overly anxious runner would accidentally begin the 
					race before the starting gun was fired.
 | 1. You can’t begin the project yet. You’re going to have to 
					wait until the plan is thoroughly developed. Don’t jump the 
					gun. 
 2. You bought your son a football and he’s only six weeks 
					old. Don’t you think you’re jumping the gun a little?
 | 
				
					| jump through a 
					hoop | obey any order | He is always ready to
					jump through a hoop for his boss. | 
				
					| jump to 
					conclusions | make quick conclusions | You should not 
					jump to conclusions until you know all the facts. | 
				
					| JUMPING-OFF POINT | a starting place or inspiration 
 This expression is usually used for discussions or creative 
					pursuits.
 | 1. Kelly used her mother’s lasagna recipe as a jumpingoff 
					point, but added her favorite ingredients to make it the way 
					she liked it. 
 2. Joe used sheet music as a jumping-off point for his song. 
					He played the tune as written, but added to it as he went.
 | 
				
					| JUNK 
					FOOD | 
 food that is relatively unhealthy, high in sugar and fat and 
					lacking in vitamins, minerals and other body-building 
					components
 | 1. My children seem to live on junk food: hamburgers, French 
					fries, milkshakes, chips, cakes, cookies, candy, and soda 
					pop. 
 2. The parents brought snacks for the children to eat. The 
					school had asked them to bring healthy foods like fresh 
					fruit and vegetables, yogurt and cheese. They asked them not 
					to bring junk food.
 | 
				
					| just about | nearly | I waited just 
					about one hour for her to come. | 
				
					| just now | this very moment | The movie began 
					just now. | 
				
					| just off the 
					boat | naive | He acts like he is
					just off the boat. | 
				
					| just so | close to perfect | She always makes sure 
					that her hair is just so before she goes 
					out. | 
				
					| just the same | nevertheless | I told her not to come 
					early but just the same she came early 
					anyway. | 
				
					| just what the 
					doctor ordered | exactly what was needed | The extra day off from 
					work was just what the doctor ordered. |